Information recording medium, information recording/reproduction system apparatus, and information recording/reproduction method

ABSTRACT

An information recording medium of the present invention is an information recording medium in which data is recorded by using a data structure, the data structure including a file structure area and a data area. The data includes first AV data having a first attribute and second AV data having a second attribute which is different from the first attribute. The data area has continuous areas. At least one of the continuous areas includes a first extent in which at least a portion of the first AV data is recorded and a second extent in which at least a portion of the second AV data is recorded.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an information recording medium,an information recording/reproduction system apparatus and aninformation recording/reproduction method for managing AV (audio/video)data by using a file structure.

[0003] 2. Description of the Related Art

[0004] An optical disk is a type of information recording medium whichhas a sector structure. In recent years, the recording density and thecapacity of an optical disk have been increased, and optical disksusable in multimedia applications have been developed. Accordingly, ithas become important to increase the access speed so that it is possibleto interactively reproduce data using a plurality of data sets. ADVD-video disk has been developed as an optical disk capable ofinteractively reproducing video titles. A DVD-video disk contains AVdata which includes a plurality of MPEG program streams and control datawhich is used for controlling the reproduction of the AV data.

[0005] Referring to a directory structure illustrated in FIG. 9 and adata structure illustrated in FIG. 10, the structure of directoriesrecorded on a DVD-video disk and the relationship between the AV dataand the control data will now be described by way of an example. ADVD-video file 908 is recorded using a predetermined file name under apredetermined directory so that a DVD player can easily access data. Inparticular, a video directory 902 is created under a root directory 901.

[0006] The DVD-video file 908 includes AV data 907 and control data 906.The AV data 907 and the control data 906 are recorded under the videodirectory 902. In particular, the AV data 907 is recorded as a file 904named “Video.AVD”, and the control data 906 therefor is recorded as afile 903 named “Video.IFO”. A file 905 named “File-A.DAT”, which is usedin personal computers, and the like, is recorded in a location otherthan under the video directory 902. Therefore, the DVD player will noterroneously reproduce PC data.

[0007] Typically, the AV data 907 includes a plurality of video objects(hereinafter, referred to as “VOBs”). In the example illustrated in FIG.10, the AV data 907 includes VOB 1009 and VOB 1010. The VOB 1009 and theVOB 1010 are both VOBs but differ from each other in terms of theconditions under which video data and audio data represented by the VOBsare compressed or encoded. For example, the VOB 1009 may be AV data of anews program which has been compressed by the MPEG1 data compressionscheme, while the VOB 1010 may be AV data of a live baseball programwhich has been compressed by the MPEG2 data compression scheme. Thecontrol data 906 includes a program 1011 for controlling thereproduction of the AV data 907 and VOB management information 1012which is used for managing the information of each VOB. The program 1011includes a program 1001 for controlling the reproduction of the VOB 1009and a program 1002 for controlling the reproduction of the VOB 1010. Theprograms 1001 and 1002 each specify a reproduction start address 1005and a reproduction end address 1006 of the VOB. The reproduction startaddress 1005 and the reproduction end address 1006 are specified,respectively, by identification information of each of the VOBs 1009 and1010 of the AV data 907 and the number of relative bytes with respect tothe leading address of each of the VOBs 1009 and 1010. In the exampleillustrated in FIG. 10, the programs 1001 and 1002 are registered. Theprogram 1001 is programmed to reproduce a portion 1007 of the VOB 1009,and the program 1002 is programmed to reproduce a portion 1008 of theVOB 1010. Thus, program data (a VOB) can be partially reproduced byspecifying the reproduction start address and the reproduction endaddress of the VOB. VOB management information 1012 includes VOBmanagement information 1003 for managing the information of the VOB 1009and VOB management information 1004 for managing the information of theVOB 1010. Each of the VOB management information 1003 and 1004 includesvarious information for the VOB such as the type of TV broadcastingsystem, the resolution, the number of channels for audio data, thecompression schemes for video data and audio data, information used forperforming a search by specifying the time of AV data, information usedfor managing location information by GOPs (groups of pictures) definedin MPEG, and the data size of the VOB. A DVD-video disk having recordedthereon information which has the directory structure illustrated inFIG. 9 and the data structure illustrated in FIG. 10 is reproduced asfollows. Application software can read out the control data 906 andinteractively reproduce a plurality of VOBs by using a predefinedprogram.

[0008] Referring to FIGS. 7A and 7B, the relationship between thephysical structure of a DVD-RAM disk 700, which is a rewritable opticaldisk, and the logical volume space thereof will now be described. FIG.7A illustrates the physical structure of the DVD-RAM disk 700. TheDVD-RAM disk 700 includes a lead-in area 701, a DMA (defect managementarea) 702 for managing defects on the disk 700, a data area 718, and alead-out area 716 which are arranged in this order from the innerperiphery to the outer periphery of the DVD-RAM disk 700. Digital datais recorded in each of these areas, and the digital data is managed by aunit called a “sector”. The data area 718 includes a spare area 703 usedfor replacing defective sectors and an area 719 including a plurality ofzones numbered from zone 0 to zone 47. In each zone, data is recorded inblocks of 2048-byte physical sectors.

[0009] Referring to FIG. 7B, the physical sectors are numbered withphysical sector numbers (PSNs) starting from the inner periphery of thedisk 700. Physical spaces 717 of the disk 700 are specified by PSNs. Onthe other hand, the space in which user data can be recorded is definedas a volume space 720 which includes a plurality of sectors which arenumbered with logical sector numbers (LSNs). In other words, the volumespace 720 is equal to the physical space 717 minus the lead-in area 701,the DMA 702, the spare area 703, a defective sector 711, a guard area715 provided between two adjacent zones, and the lead-out area 716. Thedefective sectors 711 are sectors which have been detected as beingdefective by a certification operation performed during aninitialization of the disk 700. The PSNs of the defective sectors 711are registered and managed in a PDL (primary defect list) (not shown)provided in the DMA 702. A defective sector 721 which have been detectedas being defective while recording data onto the disk 700 are replacedwith spare sectors from the spare area 703 by a linear replacementmethod and registered in an SDL (secondary defect list) (not shown)provided in the DMA 702.

[0010] Next, FIG. 8 illustrates an example of a data structure whichwould result when the various files as mentioned above are recorded onthe rewritable disk 700 by using a volume file structure 800 as definedin the ECMA 167 standard. The upper portion and the lower portion ofFIG. 8 correspond to the inner periphery and the outer periphery of thedisk 700, respectively. Sectors in the volume space 720 are numberedwith the logical sector numbers (LSNs) starting from the leading sectorof the volume space 720. A volume structure area 801 includes recordedtherein information which is used for logically handling the disk 700 asa volume, as well as location information of a space bit map 821, andlocation information of a file entry 822 of the root directory. Whilethe file set descriptor is defined as a file structure according to theECMA 167 standard, the file set descriptor is treated herein as a volumestructure for the sake of simplicity. It is also assumed herein thatfiles are accessed by using their logical sector numbers for the sake ofsimplicity, though they are typically accessed by using their logicalblock numbers.

[0011] A file structure area 802 is an area in which a descriptor fordefining the file structure is recorded. The file structure area may berecorded in a distributed manner in the volume space 720. The space bitmap 821 is a bit map which is used for managing, by blocks of sectors,free areas in the volume space 720 to which a file structure or data canbe allocated. The space bit map 821 includes location information ofunallocated areas 805 and 807. The file entry 822 includes a descriptortag 851 indicating that the descriptor is a file entry, attributeinformation 852 which specifies attribute information of the file usedby the file system, e.g., the recording date, and an allocationdescriptor 853 for managing the recording location information of a fileor a directory. The allocation descriptor 853 has the same datastructure as that shown for an allocation descriptor 834. A series ofcontinuous areas in which data is recorded is called an “extent”. Anextent is specified by a length 865 thereof and a start location 866thereof. A directory includes one or more file identifier descriptors,and a file identifier descriptor is recorded for every sub-directory orfile which is registered in the directory. A file identifier descriptor823 includes a descriptor tag 854 indicating that the descriptor is afile identifier descriptor, a file name 855 which specifies a file or adirectory, and location information 856 of the file entry. Since theroot directory 901 (FIG. 9) includes the video directory 902 and theFile-A.DAT file 905, the file identifier descriptors 823 and 824 arerecorded for the video directory 902 and the File-A.DAT file 905,respectively. Similarly, other directories and files are managed by fileidentifier descriptors and file entries 825 to 830.

[0012] Next, a method for managing the AV data 907 will be described.Typically, AV data has a large data size and is divided into a pluralityof portions which are recorded in a plurality of areas on the disk in adistributed manner. For example, when AV data having an average datarate of 5 Mbps (megabits/sec) is recorded for one hour, the size of therecorded data will be 2 GB (gigabytes). Moreover, after repeatedlyediting, deleting and adding data, the free areas are typicallyscattered on the disk. On such a disk whose free areas have beenscattered, new AV data is recorded in a distributed manner in aplurality of extents. In FIG. 8, the AV data is recorded in adistributed manner in extents 837, 839, 841 and 842. In such a case,since the volume file structure 800 does not manage the contents of thedata to be recorded, a portion of a VOB 881 and a portion of a VOB 882near the boundary therebetween will be recorded in the same extent(extent 841). The location information of these extents 837, 839, 841and 842 is recorded in an allocation information area 803 by usingallocation descriptors. Since an AV file, as compared to other files,requires a larger number of allocation descriptors to be registered, itmay not be possible to register all the allocation descriptors in thefile entry 830 which is limited to a size of 1 sector or less.Therefore, location information of the new allocation information area803 is registered in the location information 862 of the allocationinformation area in the file entry 830. The allocation information area803 has an allocation extent descriptor 831 in the leading positiontherein, followed by allocation descriptors 832, 833, 834 and 835 whichare continuously registered immediately after the allocation extentdescriptor 831. The allocation extent descriptor 831 has a descriptortag 863 indicating that the descriptor is an allocation extentdescriptor and a length 864 of the allocation descriptor which isregistered immediately after the allocation extent descriptor 831. Theallocation descriptors 832, 833, 834 and 835 specify the respectiveextents 837, 839, 841 and 842 of the AV data 907 by the length 865 andthe start location 866 thereof.

[0013] Next, a method for reproducing the AV data 907 based on theprograms 1001 and 1002 of the control data 906 will be described. Theprograms 1001 and 1002 specify the reproduction start address 1005 andthe reproduction end address 1006 of the VOB by the relative address ofthe AV data 907 with respect to the leading address of the AV data 907.Therefore, in order to find the recording location of the AV data to beactually reproduced, the allocation descriptor in the allocationinformation area 803 is read out and the logical sector number iscalculated therefrom. The reproduction start location is obtained byadding together the lengths 865 of the extents which are registered inthe allocation descriptors sequentially starting from the allocationdescriptor 832. In particular, when the accumulated length equals thereproduction start location in the AV data, the logical sector number atthat time represents the reproduction start location on the disk. The AVdata is reproduced by using the allocation descriptor which correspondsto the logical sector number thus obtained. The reproduction endlocation is calculated in a manner similar to that for the reproductionstart location. The reproduction of the AV data ends when theaccumulated length of the extents 837, 839, 841 and 842 equals thereproduction end address.

[0014] However, with the above-described volume file structure 800, thereproduction of AV data may be discontinuous when the AV data is editedbecause the data rate information of the recorded areas is not managed.If a table for managing the data rate is created for every recordedarea, the size of the table information will be large such that itcannot be managed by a consumer product whose memory size is limited.

SUMMARY OF THE INVENTION

[0015] According to one aspect of this invention, there is provided aninformation recording medium in which data is recorded by using a datastructure, the data structure including a file structure area and a dataarea. The data includes first AV data having a first attribute andsecond AV data having a second attribute which is different from thefirst attribute. The data area has continuous areas. At least one of thecontinuous areas includes a first extent in which at least a portion ofthe first AV data is recorded and a second extent in which at least aportion of the second AV data is recorded.

[0016] In one embodiment of the invention, the file structure areaincludes an allocation information area in which a first allocationdescriptor and a second allocation descriptor are recorded, the firstallocation descriptor and the second allocation descriptor respectivelyrepresenting locations of the first extent and the second extent inwhich the first AV data and the second AV data are recorded.

[0017] In one embodiment of the invention, each of the first AV data andthe second AV data, which are recorded/reproduced by blocks of sectors,is recorded as a file by using the file structure.

[0018] In one embodiment of the invention, a file entry is recorded inthe file structure area, the file entry representing information whichspecifies the first and second allocation descriptors.

[0019] In one embodiment of the invention, the first allocationdescriptor includes information representing a length of the firstextent and information representing a start location of the firstextent. The second allocation descriptor includes informationrepresenting a length of the second extent and information representinga start location of the second extent.

[0020] In one embodiment of the invention, each of the first AV data andthe second AV data has pack header and packet data for every sector.

[0021] In one embodiment of the invention, a difference between firsttime information and second time information recorded in a leadingsector and a last sector, respectively, of the extent and a data size ofAV data recorded in the extent represent an average data rate which isrequired for a transfer of the AV data recorded in the extent.

[0022] In one embodiment of the invention, the pack header includes timeinformation representing a time relating to a transfer of the packetdata.

[0023] According to another aspect of this invention, there is provideda data recording method for recording data on an information recordingmedium in which the data is recorded by using a data structure, the datastructure including a file structure area and a data area. The dataincludes first AV data having a first attribute and second AV datahaving a second attribute which is different from the first attribute.The data area has continuous areas. At least one of the continuous areasincludes a first extent in which at least a portion of the first AV datais recorded and a second extent in which at least a portion of thesecond AV data is recorded. The file structure area includes anallocation information area in which a first allocation descriptor and asecond allocation descriptor are recorded, the first allocationdescriptor and the second allocation descriptor respectivelyrepresenting locations of the first extent and the second extent inwhich the first AV data and the second AV data are recorded. The datarecording method includes: a first step of recording the first AV dataand the second AV data in the first extent and the second extent,respectively; a second step of creating the first allocation descriptorand the second allocation descriptor; and a third step of recording thefirst allocation descriptor and the second allocation descriptor in theallocation information area.

[0024] According to still another aspect of this invention, there isprovided a data editing method using an information recording medium inwhich data is recorded. The data includes AV data which isrecorded/reproduced by blocks of sectors and includes a plurality of AVdata portions, the AV data portions each corresponding to one of thesectors and having time information. The data area includes first andsecond continuous areas, each of the first area and the second areaincluding a plurality of the sectors for recording a plurality of the AVdata portions. The data editing method includes: a first step of readingout a leading sector and a last sector of each of the continuous areasso as to obtain first time information corresponding to the leadingsector and second time information corresponding to the last sector; asecond step of reading out an edition point sector corresponding to apredetermined edition point so as to obtain third time informationcorresponding to the edition point sector; and a third step ofdetermining whether or not the AV data is continuously reproduciblebased on a size of the first and second continuous areas, the first timeinformation, the second time information, and the third timeinformation.

[0025] In one embodiment of the invention, the data editing method usesa data structure, the data structure including a file structure area anda data area. The file structure area includes an allocation informationarea in which a first allocation descriptor and a second allocationdescriptor are recorded, the first allocation descriptor and the secondallocation descriptor respectively representing locations of a firstextent and a second extent, the first extent and the second extentcorresponding respective to the first and second continuous areas inwhich the AV data is recorded. The third step determines whether or notthe AV data is continuously reproducible based on the first allocationdescriptor, the second allocation descriptor, the first timeinformation, the second time information, and the third timeinformation, the first and second allocation descriptors representinglocation information of the first and second extents, respectively.

[0026] In one embodiment of the invention, the data area includes anarea in which information representing locations of the first and secondcontinuous areas is recorded as a portion of control data. The thirdstep comprises the step of obtaining the information representing thelocations of the first and second continuous areas based on the controldata.

[0027] In one embodiment of the invention, the file structure areaincludes an area in which a file entry is recorded, the file entryrepresenting the locations of the first extent and the second extent.The third step comprises a step of obtaining information representingthe locations of the first extent and the second extent based on thefile entry.

[0028] In one embodiment of the invention, the data area includes anarea in which control data is recorded, the control data includinginformation representing the locations of the first extent and thesecond extent. The third step comprises a step of obtaining informationrepresenting the locations of the first extent and the second extentbased on the control data.

[0029] According to still another aspect of this invention, there isprovided an information recording system apparatus for recording data onan information recording medium in which data is recorded by using adata structure, the data structure including a file structure area and adata area. The data includes first AV data having a first attribute andsecond AV data having a second attribute which is different from thefirst attribute. The data area has continuous areas. At least one of thecontinuous areas includes a first extent in which at least a portion ofthe first AV data is recorded and a second extent in which at least aportion of the second AV data is recorded. The file structure areaincludes an allocation information area in which a first allocationdescriptor and a second allocation descriptor are recorded, the firstallocation descriptor and the second allocation descriptor respectivelyrepresenting locations of the first extent and the second extent inwhich the first AV data and the second AV data are recorded, theinformation recording system apparatus comprising a data recordingsection for recording the first AV data and the second AV data in thedata area. The information recording system apparatus includes: a datarecording section for recording the first AV data and the second AV datain the data area; an AV file structure processing section for creating afile entry which is used for managing the first AV data and the secondAV data and recording the file entry in the file structure area; and anAV allocation structure processing section for creating the firstallocation descriptor and the second allocation descriptor and recordingthe first allocation descriptor and the second allocation descriptor inthe allocation information area.

[0030] According to still another aspect of this invention, there isprovided an information recording system apparatus for editing data byusing an information recording medium in which the data is recorded byusing a data structure, the data structure including a file structurearea and a data area. The data includes AV data which isrecorded/reproduced by blocks of sectors and includes a plurality of AVdata portions, the AV data portions each corresponding to one of thesectors and having time information. The data area includes a firstextent and a second extent, each of the first extent and the secondextent including a plurality of the sectors for recording a plurality ofthe AV data portions. The file structure area includes an allocationinformation area in which a first allocation descriptor and a secondallocation descriptor are recorded, the first allocation descriptor andthe second allocation descriptor respectively representing locations ofthe first extent and the second extent. The information recording systemapparatus includes: an AV file structure processing section for readingout the first allocation descriptor and the second allocation descriptorfrom the allocation information area so as to obtain locationinformation of the first extent and the second extent; and an AVallocation structure processing section for reading out a leading sectorand a last sector of each extent so as to obtain first time informationcorresponding to the leading sector and second time informationcorresponding to the last sector. The AV allocation structure processingsection reads out an edition point sector corresponding to apredetermined edition point so as to obtain third time informationcorresponding to the edition point sector. The AV allocation structureprocessing section determines whether or not the AV data is continuouslyreproducible based on the first allocation descriptor, the secondallocation descriptor, the first time information, the second timeinformation, and the third time information.

[0031] According to still another aspect of this invention, there isprovided an information recording medium in which data is recorded byusing a data structure, the data structure including a file structurearea and a data area, wherein the data area has physically continuousareas, AV data being recorded in at least some of the physicallycontinuous areas.

[0032] In one embodiment of the invention, the file structure areaincludes an allocation information area in which an allocationdescriptor indicating a location of an extent is recorded, the extentbeing one of the physically continuous areas in which the AV data isrecorded.

[0033] According to still another aspect of this invention, there isprovided a data recording method for recording data on an informationrecording medium in which the data is recorded by using a datastructure, the data structure including a file structure area and a dataarea, wherein the data area has physically continuous areas. The datarecording method includes the steps of: recording AV data in thephysically continuous areas; creating an allocation descriptorindicating a location of an extent, the extent being one of thephysically continuous areas in which the AV data is recorded; andrecording the allocation descriptor in the allocation information area.

[0034] According to still another aspect of this invention, there isprovided an information recording system apparatus for recording data onan information recording medium in which data is recorded by using adata structure, the data structure including a file structure area and adata area, wherein the data area has physically continuous areas. Theinformation recording system apparatus includes: a section for recordingAV data in the physically continuous areas; a section for creating anallocation descriptor indicating a location of an extent, the extentbeing one of the physically continuous areas in which the AV data isrecorded; and a section for recording the allocation descriptor in theallocation information area.

[0035] Thus, the invention described herein makes possible theadvantages of providing an information recording medium, an informationrecording/reproduction method, and an information recording/reproductionsystem apparatus, which is capable of managing the data rate for everyarea in which AV data is recorded and with which it is possible toefficiently edit the AV data while ensuring continuous reproduction ofthe AV data.

[0036] These and other advantages of the present invention will becomeapparent to those skilled in the art upon reading and understanding thefollowing detailed description with reference to the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037]FIG. 1 is a block diagram illustrating a configuration of aninformation recording/reproduction system apparatus according to oneembodiment of the present invention;

[0038]FIG. 2 is a flow chart illustrating a recording operationperformed by using an information recording/reproduction systemapparatus according to one embodiment of the present invention;

[0039]FIG. 3 is a data structure diagram illustrating the areaconfiguration according to one embodiment of the present invention;

[0040]FIG. 4 illustrates a simulation result illustrating changes in thestate of a track buffer during the reproduction of the AV data recordedon the information recording medium of the present invention;

[0041]FIG. 5 is a flow chart illustrating an editing operation performedby using an information recording/reproduction system apparatusaccording to one embodiment of the present invention;

[0042]FIG. 6 illustrates another simulation result illustrating changesin the state of a track buffer during the reproduction of the AV datarecorded on the information recording medium according to one embodimentof the present invention;

[0043]FIGS. 7A and 7B are diagrams illustrating a physical structure ofa conventional information recording medium;

[0044]FIG. 8 is a data structure diagram illustrating the areaconfiguration of a conventional information recording medium;

[0045]FIG. 9 is a diagram illustrating a conventional file directorystructure; and

[0046]FIG. 10 is a diagram illustrating conventional data structures forcontrol data and AV data.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] Embodiments of the present invention will now be described withreference to the figures.

Embodiment 1

[0048] One embodiment of the present invention will now be described.This embodiment is directed to an information recording/reproductionsystem apparatus for recording/reproducing files to/from an informationrecording medium such as a DVD-RAM disk in which data is recorded byblocks of sectors, wherein the files are managed by using the filestructure as defined in the ECMA 167 standard. The data structure ofsuch an information recording medium will also be discussed below.

[0049]FIG. 1 is a block diagram illustrating the configuration of aninformation recording/reproduction system apparatus 400 according to thepresent embodiment. The information recording/reproduction systemapparatus 400 includes a system control section 401, an optical diskdrive unit 407, an encoder 408 and a decoder 409 which are connectedtogether via an I/O bus 406. An AV signal is input from a tuner 410 andcompressed by the encoder 408 into MPEG program stream data(hereinafter, referred to as “AV data”). After being subjected to apredetermined process in the system control section 401, the compresseddata is recorded onto the disk 700 which has been loaded into theoptical disk drive unit 407. In an AV data reproduction, data ofinterest is read out from the disk 700 in the optical disk drive unit407 under the control of the system control section 401. The read AVdata is converted by the decoder 409 into an AV signal, and the decodedimages and sounds are reproduced by a TV 411. The system control section401 is implemented by a microprocessor including a control program andan arithmetic memory. The system control section 401 further includes acontrol data processing section 402 for processing the control data 906(FIGS. 9 and 10) which is used for controlling the reproduction of theAV data, a control data memory 403 for storing the control information,a file system processing section 404 for processing file structureinformation, and a file system memory 405 for storing the processedinformation. The memories 403 and 405 may be provided by dividing onememory circuit into two sections. The control data 906 has a datastructure as described earlier with reference to FIG. 10. The controldata processing section 402 includes a program processing section 421for processing a program and a VOB information processing section 422for processing information of VOBs. The control data memory 403 includesa program memory 431 and a VOB information memory 432. The file systemprocessing section 404 includes a file structure processing sections 441and 442, an AV file structure processing section 443, an AV allocationstructure processing section 444, a data recording section 445, and adata read section 446. In order to store information processed throughthese sections, the file system memory 405 includes a file structurememory 451, an AV allocation structure memory 452, and a track buffer453.

[0050] A recording operation using the informationrecording/reproduction system apparatus 400 for recording the AV data907 and the associated control data 906 onto an information recordingmedium in which only the File-A.DAT file has been recorded under theroot directory 901 in the directory structure diagram illustrated inFIG. 9 will be described below.

[0051]FIG. 3 illustrates a data structure 100 after the video directory902, the Video.IFO file 903 and the Video.AVD file 904 have beenrecorded under the root directory 901 (as shown in FIG. 9) in a manneras shown in the recording operation flow chart of FIG. 2. FIG. 3illustrates a physical space in order to clearly show physicallycontinuous areas for reproducing AV data.

[0052] When the disk 700 is inserted into the optical disk drive unit407 and the user instructs system control section 401 to record AV data,the file system processing section 404 is activated. First, aninstruction is made to read out a volume structure area 101 from thedisk 700 to the optical disk drive unit 407 by using the data readsection 446, and the read information is stored in the file structurememory 451. The file structure processing section 441 analyzes thevolume structure and successively reads out information in a filestructure area 102 to the file structure memory 451 starting from theinformation of a space bit map 121. At this time, the file structureprocessing section 441 inquires of the optical disk drive 407 locationinformation of the defective sectors 711, 721 registered in PDLs or SDLsand location information of the guard area 715 between two adjacentzones as non-data area information which cannot be seen from the volumespace of the disk inserted in the optical disk drive 407. The non-dataarea information obtained from the optical disk drive 407 is read out tothe program memory 431 (“start-up” step: S501 in FIG. 2).

[0053] In order to continuously reproduce AV data 183, the AV allocationstructure processing section 444 searches for a free area having apredetermined size, e.g., equal to or greater than 5 MB, based on theinformation of the space bit map 121 and registers AV data areas 105,107, 109 and 110 in the AV allocation structure memory 452 as AVrecordable areas. At this time, the AV recordable area is divided alongthis boundary if the AV recordable area includes any non-data areaswhich are physically managed even if the AV recordable area hascontinuous logical sector numbers (“search for AV allocation area” step:S502 in FIG. 2).

[0054] Although not shown, when the user instructs the system controlsection 401 to start recording AV data, the AV data is transmitted fromthe tuner 410 via the encoder 408 and recorded in the previously foundAV recordable areas (the AV data areas 105, 107, 109 and 110). Inparticular, a VOB 181 is recorded in extents 137, 139 and 141. The VOB181 includes a program stream, and therefore has a pack header 170 andpacket data 171 for every logical sector. In the pack header 170, a SCR(system clock reference) is recorded as information representing theamount of time required for a transfer of the packet data 171 to thedecoder 409. During reproduction, each sector is transferred to thedecoder 409 within the amount of time indicated by the SCR so as toensure continuous decoding of AV data (“record VOB data” step: S503 inFIG. 1).

[0055] The VOB information processing section 422 stores in the VOBinformation memory 432 parameters for the compression of AV data, thedata size of each GOP as defined in MPEG, and the reproduction timeinformation, which have been output from the encoder 408, and createsthe information of the control data of the VOB 181 (“create VOBinformation” step: S504 in FIG. 1).

[0056] The AV allocation structure processing section 444 creates anallocation extent descriptor 131 and allocation descriptors 132, 133 and134 corresponding to the extents 137, 139 and 141, respectively (“createAV allocation structure” step: S505 in FIG. 1).

[0057] The VOB information processing section 422 determines whether itis necessary to record another VOB (step: S506 in FIG. 1). If the VOBrecording has been finished (“Yes” in S506), the process proceeds tostep S507. If it is necessary to record another VOB (“No” in S506), thesteps from S503 to S505 are performed. For example, when a live baseballprogram is to be output from the tuner 410 following a news program, thenews program and the live baseball program are recorded as the VOB 181and the VOB 182, respectively (step of determining whether VOB datarecording has been finished: S506).

[0058] The VOB 182 is recorded as an extent 142 and an allocationdescriptor 135 of the VOB 182 is created in a manner similar to that forthe extents 137, 139 and 141. The extents 141 and 142 are physically asingle continuous area. However, this single continuous area is dividedinto the extents 141 and 142 along the boundary between the VOB 181 andthe VOB 182 (S503 to S505).

[0059] The VOB information processing section 422 confirms the recordingof the VOB 182, after which the file system processing section 404 isactivated. The AV allocation structure processing section 444 recordsthe information of the AV allocation structure memory 452 in an AVallocation information area 103 (“record AV allocation structure”step:S507 in FIG. 2).

[0060] The AV file structure processing section 443 creates a file entryof an AV file in the file structure memory 451 so as to manage the AVdata, and records the file entry in a file entry area 130 (“record AVfile structure” step: S508 in FIG. 2).

[0061] The program processing section 421 creates, and stores in theprogram memory 431, a program in which the user specifies a portion orportions of the recorded AV data to be reproduced or the order ofreproduction for the portions to be reproduced (“create programinformation” step: S509 in FIG. 2).

[0062] The control data processing section 402 records the informationof the program memory 431 and the VOB information memory 432 as controldata 136 in a data area 104 (“record control data” step: S510 in FIG.2).

[0063] In order to manage the control data 136 as the Video.IFO filedata, the file structure processing section 442 creates a file entry onthe file structure memory 451, and records a file entry 129 in the filestructure area 102. Moreover, a directory for managing an AV file andthe associated control file is recorded in the file structure area 102as a sub-directory under the root directory, and a file identifierdescriptor 123, a file entry 126, and file identifier descriptors 127and 128 are recorded (“record main file structure” step: S511 in FIG.2).

[0064] The AV allocation information area 103 may be recorded in thefile entry area 130 if the file entry thereof is of a size less than orequal to 1 sector.

[0065] Next, a method for continuously reproducing AV data will bedescribed with reference to FIGS. 1 and 4. Referring to FIG. 1, the data(an MPEG signal) read out from the disk 700 in the optical disk driveunit 407 is once stored in the track buffer 453. Then, the MPEG signalis decompressed by the decoder 409 into a video signal which is in turndisplayed as an image on the TV 411.

[0066] Referring to FIG. 4, the AV data is read out from continuousareas of the disk 700 at a constant data rate Vr (data reading rate ofthe optical disk drive 407), and stored in the track buffer 453. The AVdata stored in the track buffer 453 is transferred to the decoder 409 ata AV data transfer rate Vo. Since the AV data transfer rate Vo is lessthan the data rate Vr, the AV data is stored in the track buffer 453 ata rate of Vr-Vo. When the optical disk drive 407 accesses an area otherthan the AV data areas 105, 107, 109 and 110, the AV data transfer intothe track buffer 453 discontinues. Therefore, the amount of the AV datain the track buffer 453 decreases at a rate of Vo.

[0067]FIG. 4 illustrates changes in the amount of data in the trackbuffer 453 during the reproduction of the AV data from the extents 137to 142 illustrated in FIG. 3. The AV data transfer rate for each of theextents 137, 139, 141 and 142 can be obtained based on: the differencebetween the SCR recorded in the leading sector of each of the extentsand the SCR recorded in the last sector of each of the extents; and thedata size of the AV data recorded in each of the extents.

[0068] Since the contents of the AV data recorded in the extent 141 andthe contents of the AV data recorded in the extent 142 are differentfrom each other, the SCR recorded in the last sector of the extent 141and the SCR recorded in the leading sector of the extent 142 are notrelated with each other.

[0069] The AV data transfer rate for the extent 137 is obtained based onSCR(1) and SCR(2) which are recorded in the leading sector and the lastsector, respectively, of the extent 137. The AV data transfer rate forthe extent 139 is obtained based on SCR(3) and SCR(4) which are recordedin the leading sector and the last sector, respectively, of the extent139. The AV data transfer rate for the extent 141 is obtained based onSCR(5) and SCR(6) which are recorded in the leading sector and the lastsector, respectively, of the extent 141. The AV data transfer rate forthe extent 142 is obtained based on SCR(7) and SCR(8) which are recordedin the leading sector and the last sector, respectively, of the extent142.

[0070] The AV data transfer rates for the extents 137, 139, 141 and 142are hereinafter denoted as Vo(1), Vo(2), Vo(3) and Vo(4), respectively.

[0071] In a time period T1 to T2 during which the AV data is read outfrom the extent 137, the AV data is stored in the track buffer 453 at arate of Vr-Vo(1). Then, in a time period T2 to T3 during which the drive407 accesses an unallocated area 106, the operation of reading out theAV data from the extents discontinues. Therefore, the AV data in thetrack buffer 453 is consumed at a rate of Vo(1). Similarly, in a timeperiod T3 to T4 during which the AV data is read out from the extent139, the AV data is stored in the track buffer 453 at a rate ofVr-Vo(2). In a time period T4 to T5 during which the drive 407 accessesa data area 108, the AV data in the track buffer 453 is consumed at arate of Vo(2). In time periods T5 to T6 and T6 to T7 during which the AVdata is read out from the extents 141 and 142, respectively, the AV datais stored in the track buffer 453 at a rate of Vr-Vo(3) and at a rate ofVr-Vo(4), respectively. Thus, it is possible to ensure the continuousreproduction of AV data as long as the amount of data in the trackbuffer 453 does not decrease to zero.

[0072] Next, specific criteria which are used for determining whether AVdata recorded in two areas can be continuously reproduced will bediscussed.

[0073] The minimum physically continuous extent length N_ecc requiredfor continuous reproduction of AV data can be expressed as follows:

N _(—) ecc≧VoxTj/((16×8×2048)×(1−Vo/Vr))   (Expression 1)

[0074] where the minimum extent length N_ecc is the number of ECC (errorcorrection code) blocks in the extent (assuming that a length of one ECCblock equals 16 sectors), Vo is the average data rate (in Mbps) of therecorded AV data, Tj is-the access time (in secs) from the innerperiphery to the outer periphery of the disk 700, and Vr is the constantdata reading rate (in Mbps) at which a reproduction apparatus reads outdata from a series of continuous areas.

[0075] The access time of an optical disk drive is substantiallyconstant for any distance to the data being accessed which is equal toor greater than a certain distance. Therefore, it is effective to employthe access time from the inner periphery to the outer periphery of thedisk 700 as a common access time.

[0076] Based on actually recorded data, the average data rate Vo can beexpressed as follows:

Vo=(N_pack−1)×2048×8/(27000000/(SCR(i)−SCR(i−1))   (Expression 2)

[0077] where N_pack is the number of logical sectors in an extent,SCR(i) is an SCR value recorded in the last logical sector of the extent(obtained by counting the number of 27 MHz clock signals), and SCR(i−1)is an SCR value recorded in the first logical sector in the extent.

[0078] Where some small-sized access areas (unallocated areas, dataareas) having no AV data therein are included between extents, theminimum extent length can be expressed as follows:

Nt _(—) ecc≧dN _(—) ecc+Vox(Tj+Ts)/((16×8×2048)×(1−Vo/Vr)   (Expression3)

[0079] where the minimum extent length Nt_ecc is the total length of theaccess areas (unallocated areas, data areas) (in units of the number ofECC blocks) included between extents, dN_ecc is the total length of eachaccess area (in units of the number of ECC blocks), and Ts is the totalamount of time for which each access area is accessed. This access timeis defined as Nt_ecc×16×8×2048/Vr.

[0080] Using Expression 3, it is possible to determine, for example,whether the amount of data in the track buffer 453 would decrease tozero when reading out AV data from the extents 137 and 139 where theunallocated area 106 having no AV data recorded thereon exists betweenthe extents 137 and 139. The average data rate Vo can be calculated asfollows:

Vo=(N_pack−2)×2048×8/(27000000/(SCR(2)−SCR(1)+SCR(4)−SCR(3)))  (Expression 4)

[0081] where N_pack is the total number of sectors in the extents 137and 139.

[0082] Generally, the average data rate Vo for a number k of extents canbe calculated as follows:

Vo=(N_pack−k)×2048×8/(27000000/Σ(SCR(i)−SCR(i−1)))   (Expression 5)

[0083] where Σ(SCR(i)−SCR(i−1)) is a value obtained by adding together,for all the extents, the difference between the SCR value of the firstsector of each extent and the SCR value of the last sector of theextent.

[0084] Next, referring to the flow chart of FIG. 5, an operation ofediting the AV data as illustrated in FIG. 4 by using the informationrecording/reproduction system apparatus 400 of FIG. 1 will be described.

[0085] When the user instructs the information recording/reproductionsystem apparatus 400 to edit the AV data, the file system processingsection 404 is first activated to instruct the data read section 446 toread out the volume structure area 101 from the disk 700 to the opticaldisk drive 407. The read information is stored in the file structurememory 451. The file structure processing section 441 analyzes thevolume structure and reads out the file structure area 102 to the filestructure memory 451.

[0086] Then, the file structure processing section 441 searches for thevideo directory 902, the Video. IFO file 903 and the Video.AVD file 904under the root directory 901. Then, the file structure processingsection 442 reads out the file entries 129 and 130 to the file structurememory 451, analyzes the location information of the control data 136,and reads out the control data 136 to the program memory 431. Then, theAV file structure processing section 443 reads out the AV allocationinformation area 103 to the file structure memory 451 and obtains thelocation information of each extent (“read file” step: S601 in FIG. 5).

[0087] The AV allocation structure processing section 444 instructs theoptical disk drive 407 to read out the SCR recorded in the pack header170 of each extent. The information is read out to the AV allocationstructure memory 452, and the SCR values are stored in the AV allocationstructure memory 452 (“obtain SCR” step: S602 in FIG. 5).

[0088] Then, if the user specifies an edition point 1 (FIG. 4), the AVallocation structure processing section 444 instructs the optical diskdrive 407 to read out the sector information corresponding to editionpoint 1. The read information is read out to the AV allocation structurememory 452, and the SCR value is stored as SCR(9) in the AV allocationstructure memory 452 (“obtain SCR at edition point” step: S603 in FIG.5).

[0089] Then, the AV allocation structure processing section 444determines Nt_ecc according to Expression 3. Based on Expression 5 Vo(5)can be calculated as follows:

Vo=(N_pack−2)×2048×8/(27000000/(SCR(2)−SCR(1)+SCR(9)−SCR(3)))  (Expression 6)

[0090] If Nt_ecc satisfies the condition of Expression 3, the extents139 and 141 can be continuously reproduced even if the remaining portionof the extent 139 following edition point 1 is cleared (step ofdetermining whether the AV data is continuously reproducible: S604 inFIG. 5).

[0091] If the AV data is continuously reproducible (“Yes” in S604), theAV allocation structure processing section 444 updates the allocationdescriptor 133 of the extent 139 and record the updated allocationdescriptor 133 in the AV allocation information area 103.

[0092] Then, the file structure processing section 441 instructs theoptical disk drive 407 to update the space bit map on the file structurememory 451 and to update the space bit map 121 on the disk 700 so thatother data can be recorded in the cleared area of the extent 139following edition point 1 (“editing process” step: S605 in FIG. 5).

[0093] If the user specifies edition point 2 as shown in FIG. 6,Expression 3 is calculated with the SCR (10) for edition point 2, and itis determined in step S604 that the condition of Expression 3 is notsatisfied (“No” in S604). Therefore, if the remaining portion of theextent 139 following edition point 2 is cleared, the amount of data inthe track buffer 453 would decrease to zero. Thus, it would not bepossible to continuously reproduce the AV data. Therefore, in such acase, the process is terminated without performing the editing processwhich if performed would delete the data from the remaining portion ofthe extent 139.

[0094] As described above, according to the present embodiment, aplurality of extents are managed by a series of continuous SCRs, wherebythe average data rate of the data recorded on the disk 700 can becorrectly calculated. Therefore, whether continuous reproduction wouldbe ensured after an edition can be correctly determined by reading outthe first sector and the last sector of each extent without having toreproduce all the data.

[0095] As described above, by recording AV data having continuousparameters in each physically continuous area, it is possible toaccurately calculate the average data rate of the recorded data for eacharea and thus to accurately determine the track buffer in a reproductionoperation.

[0096] A plurality of different types of AV data may be recorded as aplurality of files in the video directory 902. For example, differentsets of AV data may be recorded based on the recording times and/ordates or a still image and a motion picture may be recorded separatelyas different VOBs. Alternatively, different sets of AV data may berecorded based on the titles thereof.

[0097] In the example described above, continuous areas in each of whichdata having the same attribute is recorded are managed as the extents141 and 142. However, the information of the data having the sameattribute may be recorded in attribute information 162 of the file entry130 as attribute information of an AV file, or the information of thedata having the same attribute may be recorded as a named stream byusing an extension file entry.

[0098] In the example shown above, continuous areas in each of whichdata having the same attribute is recorded are managed as the extents141 and 142, and the location information of the extent 141 and thelocation information of the extent 142 are managed by the allocationdescriptors 134 and 135, respectively. Alternatively, the informationrelating to the locations of the extents 141 and 142 may be recorded inthe Video.IFO file as a portion of the control data 136. For example,the length of each of the extents 141 and 142 may be recorded in atabular form for each of the extents as a portion of the control data136. In such a case, an area which is managed by the allocationdescriptors 134 and 135 does not have to be an area in which data havingthe same attribute is recorded. Thus, it is possible to simplify thefile structure. When determining whether the AV data can be continuouslyreproduced around an edition point, the location information of each ofthe extents 141 and 142 can be known based on the allocation descriptors134 and 135 and the lengths of the extents 141 and 142 which have beenrecorded as the control data 136. Therefore, it is possible to easilydetermine whether the AV data can be continuously reproduced around theedition point.

[0099] In the information recording medium of the present invention,areas in which the AV data is recorded are managed as extents in the AVfile structure. Therefore, it is possible to ensure the continuousreproduction of the recorded AV data. It is not necessary to read outall the sectors in which the AV data is recorded so as to examinewhether the AV data can be continuously reproduced. It is only necessaryto read out the leading sector and the last sector of each extent.Therefore, edition of AV data can be made efficiently.

[0100] Moreover, it is possible to ensure the continuous reproduction ofthe recorded AV data by managing the area in which AV data is recordedas divided extents taking into consideration a physical area in the AVfile structure in which user data cannot be recorded and the continuityof the AV data.

[0101] Various other modifications will be apparent to and can bereadily made by those skilled in the art without departing from thescope and spirit of this invention. Accordingly, it is not intended thatthe scope of the claims appended hereto be limited to the description asset forth herein, but rather that the claims be broadly construed.

1. An information recording medium in which data is recorded by using adata structure, the data structure including a file structure area and adata area, wherein: the data includes first AV data having a firstattribute and second AV data having a second attribute which isdifferent from the first attribute; the data area has continuous areas;and at least one of the continuous areas includes a first extent inwhich at least a portion of the first AV data is recorded and a secondextent in which at least a portion of the second AV data is recorded. 2.An information recording medium according to claim 1, wherein the filestructure area includes an allocation information area in which a firstallocation descriptor and a second allocation descriptor are recorded,the first allocation descriptor and the second allocation descriptorrespectively representing locations of the first extent and the secondextent in which the first AV data and the second AV data are recorded.3. An information recording medium according to claim 1, wherein each ofthe first AV data and the second AV data, which are recorded/reproducedby blocks of sectors, is recorded as a file by using the file structure.4. An information recording medium according to claim 2, wherein a fileentry is recorded in the file structure area, the file entryrepresenting information which specifies the first and second allocationdescriptors.
 5. An information recording medium according to claim 2,wherein: the first allocation descriptor includes informationrepresenting a length of the first extent and information representing astart location of the first extent; and the second allocation descriptorincludes information representing a length of the second extent andinformation representing a start location of the second extent.
 6. Aninformation recording medium according to claim 3, wherein each of thefirst AV data and the second AV data has pack header and packet data forevery sector.
 7. An information recording medium according to claim 6,wherein a difference between first time information and second timeinformation recorded in a leading sector and a last sector,respectively, of the extent and a data size of AV data recorded in theextent represent an average data rate which is required for a transferof the AV data recorded in the extent.
 8. An information recordingmedium according to claim 6, wherein the pack header includes timeinformation representing a time relating to a transfer of the packetdata.
 9. A data recording method for recording data on an informationrecording medium in which the data is recorded by using a datastructure, the data structure including a file structure area and a dataarea, wherein: the data includes first AV data having a first attributeand second AV data having a second attribute which is different from thefirst attribute; the data area has continuous areas; at least one of thecontinuous areas includes a first extent in which at least a portion ofthe first AV data is recorded and a second extent in which at least aportion of the second AV data is recorded; the file structure areaincludes an allocation information area in which a first allocationdescriptor and a second allocation descriptor are recorded, the firstallocation descriptor and the second allocation descriptor respectivelyrepresenting locations of the first extent and the second extent inwhich the first AV data and the second AV data are recorded, the datarecording method comprising: a first step of recording the first AV dataand the second AV data in the first extent and the second extent,respectively; a second step of creating the first allocation descriptorand the second allocation descriptor; and a third step of recording thefirst allocation descriptor and the second allocation descriptor in theallocation information area.
 10. (Cancelled)
 11. (Cancelled) 12.(Cancelled)
 13. (Cancelled)
 14. (Cancelled)
 15. An information recordingsystem apparatus for recording data on an information recording mediumin which data is recorded by using a data structure, the data structureincluding a file structure area and a data area, wherein: the dataincludes first AV data having a first attribute and second AV datahaving a second attribute which is different from the first attribute;the data area has continuous areas; at least one of the continuous areasincludes a first extent in which at least a portion of the first AV datais recorded and a second extent in which at least a portion of thesecond AV data is recorded; and the file structure area includes anallocation information area in which a first allocation descriptor and asecond allocation descriptor are recorded, the first allocationdescriptor and the second allocation descriptor respectivelyrepresenting locations of the first extent and the second extent inwhich the first AV data and the second AV data are recorded, theinformation recording system apparatus comprising a data recordingsection for recording the first AV data and the second AV data in thedata area, the information recording system apparatus comprising: a datarecording section for recording the first AV data and the second AV datain the data area; an AV file structure processing section for creating afile entry which is used for managing the first AV data and the secondAV data and recording the file entry in the file structure area; and anAV allocation structure processing section for creating the firstallocation descriptor and the second allocation descriptor and recordingthe first allocation descriptor and the second allocation descriptor inthe allocation information area.
 16. (Cancelled)
 17. An informationrecording medium in which data is recorded by using a data structure,the data structure including a file structure area and a data area,wherein: the data area has physically continuous areas, AV data beingrecorded in at least some of the physically continuous areas.
 18. Aninformation recording medium according to claim 17, wherein the filestructure area includes an allocation information area in which anallocation descriptor indicating a location of an extent is recorded,the extent being one of the physically continuous areas in which the AVdata is recorded.
 19. A data recording method for recording data on aninformation recording medium in which the data is recorded by using adata structure, the data structure including a file structure area and adata area, wherein the data area has physically continuous areas, thedata recording method comprising the steps of: recording AV data in thephysically continuous areas; creating an allocation descriptorindicating a location of an extent, the extent being one of thephysically continuous areas in which the AV data is recorded; andrecording the allocation descriptor in the allocation information area.20. An information recording system apparatus for recording data on aninformation recording medium in which data is recorded by using a datastructure, the data structure including a file structure area and a dataarea, wherein the data area has physically continuous areas, theinformation recording system apparatus comprising: a section forrecording AV data in the physically continuous areas; a section forcreating an allocation descriptor indicating a location of an extent,the extent being one of the physically continuous areas in which the AVdata is recorded; and a section for recording the allocation descriptorin the allocation information area.